In the past, relay devices have had a wide variety of applications with respect to various electrical energized apparatus. For example, an electric motor in a hermetic environment may, to avoid possible arcing within the hermetic environment, employ a relay device exteriorly of such environment with the relay device having normally open contacts in series with a start or auxiliary winding means of the electric motor and a relay coil in series with the run or main winding means of the electric motor. Thus, upon initial energization of the electric motor, a large current is drawn through through the main winding means causing the relay device to effect the closure of its contacts in order to energize the auxiliary winding means generally simultaneously with the energization of the main winding means of the electric motor. As the motor speed increases generally to a preselected value, the current draw of the main winding means is decreased, and the relay device drops out, i.e. effects the reopening of its contacts, thereby to disable or disconnect the auxiliary winding or disconnect it from circuit relation with the main winding means. Of course, the continued energization of the main winding means thereafter operates the electric motor generally at its preselected or synchronous speed.
One relay device well suited to this type arrangement is illustrated in Woods U.S. Pat. No. 3,130,284. This patented relay device includes an insulating housing containing movable contacts and an axially movable sleeve which is mounted within the housing so as to be movable between two positions to actuate the contacts. A reciprocable magnetic armature is slidably mounted on the sleeve, and an electrical coil is disposed on the housing for magnetically energizing the armature. When a sufficient current is drawn through the coil, the armature is magnetically attracted against a spring force to move the sleeve and drive the contacts to their closed position. When the current drawn through the coil drops below a specified or drop-out level, the magnetic field of the coil is correspondingly reduced, and the spring force overcomes the reduced magnetic attraction of the coil with respect to the armature drawing it against the contacts to effect the re-opening of the contacts. This relay device is mechanically mounted to a cooperating supporting structure by a generally U-shaped bracket having a pair of depending legs for grippingly receiving the relay device, and an integral base is formed between such leg to receive screws or the like which threadedly engage such cooperating supporting structure.
A plug-on relay device is disclosed in a later Lee O. Woods U.S. Pat. No. 3,287,675 in which female terminals are disposed in a portion of the relay device housing for receiving in electrical contacting engagement male terminals when the relay device is plugged into such male terminals. In this arrangement, the male terminals are predeterminately mounted so as to be connected in circuit relation with a winding circuit of an electric motor which may be disposed in a hermetic environment. Still another plug-on type relay device is disclosed in a copending Lee O. Woods U.S. patent application Ser. No. 809,054 filed June 22, 1977.